This study will highlight and validate chiropractic spinal manipulative therapy (CSMT) for migraine. If the method proves to be effective, it will provide a new non-pharmacological treatment option for migraine. This is especially important since some migraineurs do not tolerate acute and/or prophylactic medicine, due to side effects or contraindications due to comorbidity of other diseases while others do not have effect. Thus, alternative treatment options are warranted. The applied methodology of the study will aim towards the highest possible research standards. This international study is a collaboration between Akershus University Hospital, University of Oslo (UiO), Norway and Macquarie University, Australia. The multidisciplinary professional backgrounds are physiotherapy, chiropractic and medicine. By increasing the methodological quality of the investigators research to a very high level, the investigators see the method to work as a guide to increase the quality of chiropractic research in the future, as previous randomized clinical trials (RCTs) of migraine used methodology showing room for improvement.